Temperature-reporting oscillator
In an integrated circuit device having a microelectromechanical-system (MEMS) resonator and a temperature transducer, a clock signal is generated by sensing resonant mechanical motion of the MEMS resonator and a temperature signal indicative of temperature of the MEMS resonator is generated via the temperature transducer. The clock signal and the temperature signal are output from the integrated circuit device concurrently.
1 . In production or supply of an oscillator integrated circuit, the oscillator integrated circuit having a microelectromechanical systems (MEMS) resonator, circuitry operable to produce a first signal according to motion of the MEMS resonator, a temperature sensor, a storage circuit, a package exterior, and one or more pins or contacts on the package exterior, the one or more pins or contacts including a clock output pin or contact operable to output a clock signal, derived from the first signal, for usage by a clocked circuit external to the oscillator integrated circuit, the temperature sensor operable to sense an operating temperature of the MEMS resonator, the motion of the MEMS resonator being dependent on a stiffness of the MEMS resonator which varies as a function of the operating temperature, the clock signal to have a predetermined frequency, an improvement comprising:
in one or more calibration operations:
empirically measuring variation in frequency of the clock signal through a range of temperatures; and
responsively programming the storage circuit, via one of the one or more pins or contacts, to have:
first data to be applied, by the circuitry to reduce differences between the first signal and a target frequency; and
second data to be used by the clocked circuit to correct timing provided by the clock signal so as to obtain the predetermined frequency;
wherein the oscillator integrated circuit is to output, during operation of the oscillator integrated circuit, and via the one or more pins or contacts, the clock signal, a temperature signal which varies according to the operating temperature of the MEMS resonator, and information to be used by the clocked circuit, dependent on each of the second data and the temperature signal, and notwithstanding the reduction of the differences between the first signal and the target frequency, to correct for residual frequency error between the timing provided by the clock signal and the target frequency, the information being dependent on the second data.
2 . The improvement of claim 1 wherein:
the MEMS resonator is an electrostatic resonator;
the first data comprises frequency tuning data; and
the circuitry is operable to generate a bias voltage to be applied to the electrostatic resonator, to urge the motion of the resonator toward a predetermined resonator frequency, and thereby reduce the differences between the resonator signal and the target frequency.
3 . The improvement of claim 1 wherein:
the MEMS resonator is a piezoelectric resonator;
the first data comprises frequency tuning data; and
the circuitry is operable to generate a signal to be applied to urge the resonator toward a predetermined resonator frequency, and thereby reduce the differences between the first signal and the target frequency.
4 . The improvement of claim 1 wherein:
the second data comprises polynomial coefficients corresponding to nonlinear variation of the first signal as a function of linear variation in the operating temperature.
5 . The improvement of claim 4 wherein the information comprises the polynomial coefficients.
6 . The improvement of claim 1 wherein the storage circuit comprises a look-up table, and wherein the information varies with the temperature signal.
7 . The improvement of claim 1 wherein:
the MEMS resonator is a first MEMS resonator and the function is a first function;
the temperature sensor is embodied in part as a second MEMS resonator, the second MEMS resonator having motion which varies as a second function of the operating temperature, the circuitry being operable to produce a second signal according to motion of the second MEMS resonator; and
the oscillator integrated circuit is to produce the temperature signal dependent on a relationship between the first signal and the second signal.
8 . The improvement of claim 1 wherein:
the improvement further comprises a first die, a second die and a thermally-conductive fill material directly connecting a surface of the first die with a surface of the second die;
the MEMS resonator is on the first die; and
the circuitry includes one or more circuit structures on the second die.
9 . The improvement of claim 1 wherein:
the storage circuit is dynamically-programmable, during operation of the oscillator integrated circuit, and via a contact of the one or more pins or contacts, to store third data; and
the oscillator integrated circuit further comprises circuitry to output the temperature signal in a manner that varies according to an operating mode, wherein the operating mode is determined according to the third data.
10 . The improvement of claim 9 wherein:
the oscillator integrated circuit comprises a multifunction interface, including a receiver and a transmitter each operable to transfer external communication via a same pin or contact of the one or more pins or contacts on the package exterior; and
the oscillator integrated circuit is configured such that, during operation of the oscillator integrated circuit, each of the temperature signal and the information is transmitted via the same pin or contact.
11 . The improvement of claim 1 wherein the first data comprises compensation data and wherein the clock signal represents a temperature-compensated frequency output of the oscillator integrated circuit.
12 . The improvement of claim 1 wherein the temperature signal comprises a digital temperature output corresponding to the operating temperature of the MEMS resonator.
13 . The improvement of claim 1 wherein the temperature sensor comprises a thermistor.
14 . The improvement of claim 1 wherein the first data corresponds to a value and wherein the circuitry comprises at least one of a frequency multiplier circuit or frequency division circuit operable to adjust the timing of the output signal as a function of the value.
15 . The improvement of claim 1 wherein the circuitry is to output the information on demand.
16 . In production or supply of an oscillator integrated circuit, the oscillator integrated circuit having an electrostatic microelectromechanical systems (MEMS) resonator, circuitry operable to produce a first signal according to motion of the MEMS resonator, a temperature sensor, a storage circuit, a package exterior, and one or more pins or contacts on the package exterior, the one or more pins or contacts including a clock output pin or contact operable to output a clock signal, derived from the first signal, for usage by a clocked circuit external to the oscillator integrated circuit, the temperature sensor operable to sense an operating temperature of the electrostatic MEMS resonator, the motion of the electrostatic MEMS resonator being dependent on a stiffness of the electrostatic MEMS resonator which varies as a function of the operating temperature, the clock signal to have a predetermined frequency, an improvement comprising:
in one or more calibration operations:
empirically measuring variation in frequency of the clock signal through a range of temperatures; and
programming the storage circuit, via one of the one or more pins or contacts, to have:
first data to be applied by the circuitry to generate a bias voltage for the electrostatic MEMS resonator, the bias voltage being adjusted according to the first data to reduce differences between the first signal and a target frequency; and
second data to be used by the clocked circuit to correct timing provided by the clock signal so as to obtain the predetermined frequency;
wherein the oscillator integrated circuit is to output, during operation of the oscillator integrated circuit, and via the one or more pins or contacts, the clock signal, a temperature signal which varies according to the operating temperature of the electrostatic MEMS resonator, and information to be used by the clocked circuit, dependent on each of the second data and the temperature signal, and notwithstanding the reduction of the differences between the first signal and the target frequency, to correct for residual frequency error between the timing provided by the clock signal and the target frequency, the information being dependent on the second data.
17 . The improvement of claim 16 wherein the temperature signal comprises a digital temperature output corresponding to the operating temperature of the MEMS resonator.
18 . In production or supply of an oscillator integrated circuit, the oscillator integrated circuit having a piezoelectric microelectromechanical systems (MEMS) resonator, circuitry operable to produce a first signal, a temperature sensor, a storage circuit, a package exterior, and one or more pins or contacts on the package exterior, the one or more pins or contacts including a clock output pin or contact operable to output a clock signal, derived from the first signal, for usage by a clocked circuit external to the oscillator integrated circuit, the temperature sensor operable to sense an operating temperature of the piezoelectric MEMS resonator, the motion of the piezoelectric MEMS resonator being dependent on a stiffness of the piezoelectric MEMS resonator which varies as a function of the operating temperature, the clock signal to have a predetermined frequency, an improvement comprising:
in one or more calibration operations:
empirically measuring variation in frequency of the clock signal through a range of temperatures; and
programming the storage circuit, via one of the one or more pins or contacts, to have:
first data to be applied by the circuitry to reduce differences between the first signal and a target frequency; and
second data to be used by the clocked circuit to correct timing provided by the clock signal so as to obtain the predetermined frequency;
wherein the oscillator integrated circuit is to output, during operation of the oscillator integrated circuit, and via the one or more pins or contacts, the clock signal, a temperature signal which varies according to the operating temperature of the piezoelectric MEMS resonator, and information to be used by the clocked circuit, dependent on each of the second data and the temperature signal, and notwithstanding the reduction of the differences between the first frequency and the target frequency, to correct for residual frequency error between the timing Provided by the clock signal and the target frequency, the information being dependent on the second data.
19 . The improvement of claim 18 wherein the first data corresponds to a value and wherein the circuitry comprises at least one of a frequency multiplier circuit or frequency division circuit operable to adjust timing of the output signal as a function of the value.
20 . The improvement of claim 18 wherein the first data comprises compensation data and wherein the clock signal represents a temperature-compensated frequency output of the oscillator integrated circuit.
21 . The improvement of claim 18 wherein the temperature signal comprises a digital temperature output corresponding to the operating temperature of the MEMS resonator.